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Efficacy of an ivermectin controlled-release capsule against some rarer nematode parasites of sheep
1Kathrinenhof Research Center, Merial GmbH, Rohrdorf-Lauterbach, Germany.
Abstract:
A controlled trial was conducted to evaluate the efficacy of the intraruminal ivermectin controlled-release capsule (CRC) (IVOMEC Maximizer CR Capsule for Sheep, Merial Ltd.) against induced incoming third-stage larvae and established adult infections with some rarer gastrointestinal nematode parasites of sheep. Twenty-one worm-free lambs were allocated by restricted randomisation based on body weight within sex to one of the following treatments: unmedicated control, ivermectin CRC given on Day 0 prior to induced infection, and ivermectin CRC given on Day 70 after establishment of induced infection. The ivermectin CRC delivers ivermectin at a minimum dose rate of 20 microg/kg/day for 100 days. Infections were induced by daily administration of third-stage larvae for five consecutive days. Nematodes were counted on Day 84, 14 days after treatment of established infection. The treatment with the ivermectin CRC prevented the establishment of Ostertagia leptospicularis, O. ostertagi, Bunostomum trigonocephalum, Cooperia oncophora, C. punctata, C. surnabada, Nematodirus helvetianus, N. roscidus and Strongyloides papillosus by >99% as compared with the untreated controls (p < 0.01). The administration of the ivermectin CRC reduced established adult infections of O. ostertagi, B. trigonocephalum, C. oncophora, C. punctata, C. surnabada, N. roscidus and S. papillosus by >99% (p < 0.01), and reduced established adult infections of O. leptospicularis and N. helvetianus by 96.5 and 98.4% (p < 0.01), respectively.
Insights
The intraruminal ivermectin controlled-release capsule (CRC) effectively prevents and reduces gastrointestinal nematode infections in sheep. This study demonstrates its high efficacy against various parasitic larval and adult stages.
Area of Science:
- Veterinary Parasitology
- Sheep Health
- Anthelmintic Efficacy
Background:
- Gastrointestinal nematode infections pose a significant threat to sheep health and productivity.
- Effective parasite control strategies are crucial for sustainable sheep farming.
- The intraruminal controlled-release capsule (CRC) offers a novel delivery method for anthelmintics.
Purpose of the Study:
- To evaluate the efficacy of an intraruminal ivermectin CRC against induced gastrointestinal nematode infections in sheep.
- To assess the preventative and curative effects of the ivermectin CRC on larval and adult nematode stages.
- To determine the efficacy of the ivermectin CRC against specific rare gastrointestinal nematode species.
Main Methods:
- A controlled trial involving 21 worm-free lambs allocated to unmedicated control, early-treatment, or late-treatment groups.
- Infections were induced via daily administration of third-stage larvae over five consecutive days.
- Ivermectin CRC administered on Day 0 (pre-infection) or Day 70 (post-infection establishment), delivering 20 microg/kg/day for 100 days.
Main Results:
- The ivermectin CRC demonstrated >99% efficacy in preventing the establishment of nine key nematode species.
- Established adult infections of seven nematode species were reduced by >99%.
- Efficacy against adult Ostertagia leptospicularis and Nematodirus helvetianus reached 96.5% and 98.4%, respectively.
Conclusions:
- The intraruminal ivermectin CRC is highly effective in preventing and treating gastrointestinal nematode infections in sheep.
- The CRC formulation provides sustained ivermectin release, ensuring long-term parasite control.
- This delivery system represents a valuable tool for managing nematode burdens and improving sheep welfare.